A train can be defined as a connected series of vehicles that move along a track to transport freight or passengers from one place to another. The track can be formed by two rails, but might also be a monorail or maglev guideway. Propulsion for the train is provided by a locomotive or other motors in self-propelled multiple units. The world speed record of the fastest train on rails has been set by the French TGV, in French, Train à Grande Vitesse, or in English, High Speed Train. The TGV has achieved a speed of 574.8 km/h (356 mph) in testing in 2007. Although the record for the fastest commercial speed on rail is currently held by Chinese railways at 350km/h on the Beijing–Tianjin route. TGV runs at a maximum commercial speed of 300-320 km/h, as does the German ICE. Generally, High-speed rail is very competitive in less than 3 or 4 hours distance in corridor of dense population, but often air has advantage in longer journeys. Very fast trains sometimes tilt, like the APT, the Pendolino/Freccia Rossa, or the Talgo. Tilting is a system where the passenger cars automatically lean into curves, reducing the sideways g-forces on passengers and permitting higher speeds on curves in the track with greater passenger comfort.